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RD. MONTGOMERY, Ol" NEW? YORK, N. Y., ASSIGNOR lO ELISABETH MONTGOMERY.

SHEET-METAL BEAM.

Specification forming part of Letters Patent No. 9,842, dated July 12,1853; Ressued July 2, 186'?,

T0 all whom t may concern.'

Be it known that l, R101-IARD MONTGOM- ERY, of the city, county, andState of New York, have invented or discovered a new and usefulimprovement in the manufacture of sheet-metal beams for supportingweights and resisting strains in bridges, houses, ships, and otherstructures, of which the following is a full and exact description,reference being had to the accompanying drawing, which makes part ofthis specification, and in which- Figure 'l represents a view inperspective of one of my improved beams made of a single plate; Fig. 2 atransverse section of the same; and Fig. S a view in perspective of asaddle for the support of the ends of the beam.

The object. of my invention is to produce a metallic beam of greaterlightness and strength and at less cost than has heretofore been done,and I effect this object by bending sheet metal which possesses greattextile strength into such a form as will give it the properproportions, rigidity, and transverse strength, to admit of its use as abeam for resisting great weights or strains.

It is well known that if beams be properly secured against twisting orbuckling, all other things being equal, those will possess the greatestamount of transverse strength, or support the greatest weight withoutliability to fracture, which present the greatest depth of material inthe line of pressure. By applying this test to my beam it will be seenthat it possesses greater transverse strength and stiffness than anyother beam of equal weight formed of sheet metal by bending the sameinto folds.

My beam is constructed by bending a sheet of metal into a series oflongitudinal strips, which are alternately arched and flat, the archesbeing alternately inverted, the fiat strips being arranged, vertical,parallel, and equidistant, as nearly as practicable, and each connectedto the adjacent flat strip by an inverted arch at the bottom, on the onehand; and by an uninverted arch at the top, on the other hand; thearches terminating in the parallel strips, and acting as flanges to givethem lateral stiffness, and the arches and flat strips togetherconstituting a series of folds of the sheet metal, which run lengthwiseof the beam.

In a beam thus constructed, the great depth of the parallel plates,which form the side of the folds is rendered available to support aweight, or resist strains, and as each plate is a rectangular beam ofgreat depth compared to its thickness, and as rectangular beams resistfracture by a force y proportionate to the square of their depth, I

4produce a beam of immense strength with but little weight of material.

ln the accompanying drawing of one of my beams made of a single sheet ofmetal, bent into four vertical flat strips (a), three uninverted arches(o) and four invert-ed arches (c), the flat strips and arches all runlengthwise of the beam.

lllhe span and height of the arches and the depth and number of thefolds in the series, and the manufacture of the beam by swaging,rolling, or otherwise, are matters which must he left to the judgment ofthe engineer who superintends the construction.

The ends of the beam thus constructed require a firm and stable supportat both ends, and in order more effectually to insure such a support, lhave contrived a saddle (S) which lits the under side of the beam, andhaving a broad flat base (on), is adapted to being built into, or standfirmly on the wall.

lVhen this beam is employed in ship building, it may be riveted orotherwise se- -cured to the knees or ribs so that advantage may be takenof its tensile strength as well as its stiffness.

l am aware that plates of metal for roofing and steam boilers have beenbent into a wavy form by a process commonly termed corrugation, for thepurpose of stiffening them; but in every such case, the series of foldsare comparatively shallow and instead of the strips between the archesbeing parallel and in the plane of pressure, they are inclined to eachother, and stand obliquely across the plane of pressure, in which position they would break down with a load that they could easily support ifplaced vertical and parallel 'as in my beam. And to a plate with suchinclined strips I therefore make no claim as it is not suitable for abeam.

But

What I do claim as m invention and dea beam of a pair of saddles tosupport its sire to secure by Letters atent, s ends, substantially asherein set forth. l0 l. A beam formed of sheet metal bent into Intestimony whereof, I have hereunto a series of longitudinal folds thesides of subscribed my name. 5 which are flat and parallel, and the topsand R. MONTGOMERY. bottoms uninverted and inverted arches re- Witnesses:i spectively. P. A. WATSON,

2. I also claim the combination With such I. L. SMITH.

[FIRST PmNTED 1913.]

